While synthetic plastic material has been used in many applications where wood previously was used, these have involved special profiles not acceptable as true lumber substitute products.
For instance, in the Anderson Patent EP O 586 213 A 1, the profiles for window frames were extruded from a composite material involving sawdust and a polymeric material.
Again, in U.S. Pat. No. 6,412,227, there is disclosed the use of a composite material to mold the frame members for doors and the like.
Published Canadian Application Serial No. 2,309,127 discloses a proposed member for use as a lumber substitute which member has wires embedded in a body of composite plastic material which has grooved exterior surfaces to enable such members to be fitted together with the lands between the grooves of one member fitted into the grooves of the other member and vice versa.
All such aforesaid members are one piece members requiring a substantial volume and weight of plastic synthetic material and are not acceptable as realistic simple lumber substitutes.